1. Field of the Invention:
This invention relates to a voltage detecting device for a camera.
2. Description of the Prior Art:
It has been known to find the voltage condition of a power source through variation in the flickering period of an annunciator. The voltage detecting device of this type uses an integrator which performs integration in response to a battery check operation. When the output value of this integrator reaches a predetermined value, a comparator is actuated to make an annunciation and, at the same time, a discharge circuit is formed for the integrator. Then, the integrator resumes integration. The annunciator performs flickering with these actions repeated. The integrator of such a device comprises an operational amplifier and a selected capacitor connected to the input and output terminals of the operational amplifier. However, to permit adjustment of unevenness in accuracy, the capacitor cannot be disposed within an integrated circuit board and is thus mounted on the outside of the board. Accordingly, a voltage detecting device of this kind has been troublesome in respect of selection of a capacitor and mounting of it on the circuit board.
Meanwhile, some camera which has its exposure digitally controlled with analog exposure information converted into a digital value by an A-D converter has recently been developed. In the camera of this type, the A-D converter is provided with an integrator of a high degree of accuracy. This integrator is arranged also to have a capacitor selected and mounted on the outside of a circuit board. Therefore, the use of the above stated voltage detecting device for such a digital control camera has been even more troublesome in respect of selection of and mounting of the capacitor.